An extrusion die for extruding thin films has an outlet orifice that extends along the length of the die. In operation, molten polymer flows under pressure through one or more internal flow passages in the die and leaves the die via the outlet orifice. To control the width of the thin film produced by the extrusion die, the die can be provided with a deckle system. When provided, the deckle system is inserted into the internal flow passage(s) of the die to prevent extrudate from flowing through the areas occupied by the deckle system. In this manner, the deckle system adjusts the outlet orifice width through which molten polymer can flow and, accordingly, sets the width of the extruded film produced using the die.
Deckle systems can have a variety of configurations. The deckles on an extrusion die may be internal to the die, external to the die, or both (i.e., internal and external deckles can both be provided). Internal deckle systems include one or more internal deckle members, such as full-width flags, plugs, and deckle rods. The different internal deckle components fill the end regions of respective sections of the internal flow passage(s).
A problem with existing extrusion technology is the lack of an extrusion die that can selectively produce a composite extrudate having an encapsulation arrangement, a full-width arrangement, or a naked-edge arrangement. It would be desirable to provide an extrusion die capable of such varied production and having multiple manifolds equipped with respective internal deckles that are independently adjustable by virtue of a precise, compact, easy-to-use deckle adjustment system. It would be particularly desirable to provide a method of using such an extrusion die to produce a composite extrudate having a full-width arrangement, an encapsulation arrangement, or a naked-edge arrangement.
It would also be desirable to provide methods of using an extrusion die having first and second manifolds and first and second internal deckle members received respectfully in the first and second manifolds, where one of the first and second internal deckle members is moved further into the extrusion die than the other, and where the method produces a composite extrudate having either an encapsulated arrangement or a naked-edge arrangement.